The industrial hemp is a fibre plant which provides lignocellulosic fibres for both garment textiles and composites applications due to their challenging performances. Retting is a key process of fibre extraction by impacting the mechanical extraction efficiency and the intrinsic fibres properties. After harvesting, the stems are laid on the soil and retting is performed by environmental micro-organisms. Hydrolytic enzymes secreted by micro-organisms, facilitate the fibres dissociation by removing the non-cellulosic components. To increase the production of high-value hemp fibres, it is necessary to disseminate their production to other territories and more accurately in Southern France. Nevertheless, field retting is highly dependent on the pedoclimatic conditions. The aim of this work is then to investigate the biological mechanisms involved during hemp stems retting for a careful monitoring of this process in drier environments than traditional areas ones. The evolution of the biochemical composition of fibres was firstly investigated. A decrease in amorphous components and an increase in cellulose crystallinity are observed. In parallel, the temporal dynamics of both microbial diversity and enzymatic activities are evaluated. The correlation between retting microbiology and intrinsic characteristics of fibres is examined in order to identify key criteria for controlling retting and subsequently obtaining high value fibres with homogeneous properties.